JP2886364B2 - PC composite truss beam and its construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PC composite truss beam mainly constructed as a bridge or the like and a construction method thereof.

[0002]

2. Description of the Related Art Generally, in a prestressed concrete beam having an alternating sectional force, such as a bridge girder constructed by an extrusion method or a cantilever method, a PC steel material is disposed on both upper and lower floor plates to cope with the sectional force. It is common to do.

[0003] This reinforcing method is a reasonable method. However, since a compressive stress due to a prestress is added to a compressive stress due to a bending moment during erection, a general PC beam is raised in height to reduce the stress due to the bending moment. Although it is devised to reduce it, there is a problem that the overall weight of the bridge girder increases.

Accordingly, recently, various methods of using high-strength concrete and reducing the weight by using a composite structure have been studied, but there are various problems as described below for practical use.

[0005] Among these, the dimensions of the web portion in the conventional PC box girder structure are not determined by the shear strength or the like, but are determined by the spacing between PC steel materials and the space for inserting a vibrator during concrete placement. It is generally determined based on the details (see FIGS. 19 and 20).

For this reason, even if high-strength concrete having the conventional cross-sectional shape as described above is used, it cannot be reduced to the minimum dimension of the structural details, and there is a limit to weight reduction.

As a method for reducing the weight of PC beams, FIG.
Although a composite structure with a steel structure as the web part has been developed as shown in the above, due to the high axial rigidity of the web, part of the prestress introduced into the floorboard is restrained by the web part. Therefore, there is a problem that the prestress cannot be used effectively. In particular, when high-strength concrete is used, the amount of prestress to be introduced also increases and the creep coefficient tends to increase, so not only the loss of prestress due to the restraining force of the web increases, but also the transmission into the web section The introduced introduction force (prestress loss amount) has an adverse effect as unnecessary compression force.

[0008] In addition, creep and drying shrinkage of the concrete cause a large shearing force at the joint between the steel material and the concrete, and this shearing force is not only increased when high-strength concrete is used, but also increased (concrete strength). It has been clarified by experiments that it is not expected to increase the shearing force even if the height rises), and it becomes difficult to reinforce the joint structure (divevel structure).

The present invention has been made to solve the above problems, and provides a lightweight and extremely economical PC composite truss beam capable of effectively performing reinforcement by prestress and a construction method thereof. The purpose is to:

[0010]

According to a first aspect of the present invention, there is provided a PC composite truss beam having upper and lower floor plates formed by introducing prestress over the entire length thereof, and a truss-like shape between the upper and lower floor plates. Consisting of a web part formed in
The upper and lower floor plates are formed by continuously connecting a plurality of floor plates formed by introducing a plurality of PC steel materials to introduce prestress, and joining the PC steel materials of adjacent floor plates in a tensioned state with a coupler. The joint between the floorboards is formed by introducing a prestress equivalent to the prestress amount introduced into the floorboards, and the web part is
A vertical member on both sides between the upper and lower floor plates, an inverted V-shaped side member on both sides of the vertical member in the longitudinal direction of the floor plate portion, and an X-shaped brace material between the vertical members. The truss structure is formed by joining and attaching to the upper and lower floor boards, and joining the adjacent U-shaped side member and the inverted U-shaped side member to form a truss structure.

According to a second aspect of the present invention, there is provided a PC composite truss beam having upper and lower floor plates formed by introducing prestress over the entire length thereof, and a truss-like web portion formed between the upper and lower floor plates. In the PC composite truss beam, the upper and lower floor plates are connected to a plurality of floor plates formed by inserting a plurality of PC steel members to introduce prestress and to connect the PC steel members of adjacent floor plates. Are joined in a tensioned state with a coupler to form a prestress equal to the amount of prestress introduced into the floorboard at the joint between the floorboards, and the web sections are formed on both sides of the upper and lower floorboard sections. Multiple X-shaped braces
A truss structure is formed by joining and attaching a material to the floor plate .

According to a third aspect of the present invention, there is provided a method for constructing a PC composite truss beam, wherein upper and lower floor plates formed by introducing a plurality of PC steel members to introduce a prestress, and between the upper and lower floor plates. A main unit is constructed from a plurality of vertical members and a U-shaped side member, and an inverted U-shaped side member and an X-shaped brace material, and a plurality of these main units are connected in series and an adjacent main unit is provided. The PC steels of the upper and lower floorboards are joined in a tensioned state with a coupler to introduce a prestress equal to the amount of prestress introduced into the floorboards at the joints of the floorboards, and to reverse the adjacent square-shaped side members. The truss-shaped web portion is formed by joining the U-shaped members to each other.

In the construction method of a PC composite truss beam according to a fourth aspect of the present invention, a plurality of floor boards formed by introducing a plurality of PC steel members to introduce a prestress and to form a prestress are connected. At the same time, prestresses equivalent to the amount of prestress introduced into the floorboards are introduced into the joints between the floorboards by joining the PC steel materials of the adjacent floorboards in a tensioned state with a coupler, and then the upper and lower floorboards are joined. A plurality of X-shaped brace members on both sides between the upper and lower floor boards
Attach joined to and forming a truss-like web portion.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a composite truss beam according to an embodiment of the present invention; FIG. 1)
Are the upper and lower floor boards 1a and 1b, and the upper and lower floor boards 1a and 1b.
It is constructed from a web portion 1c formed in a truss shape between 1b. The main body 1 is constructed by connecting a plurality of main units 2 in the axial direction of the main body 1 and introducing a predetermined amount of prestress over the entire length thereof.

Each main unit 2 is constructed from upper and lower floor plates 3, 4 and a web 5, and each of the upper and lower floor plates 3, 4 is formed in a rectangular plate shape from reinforced concrete using high-strength concrete, and is embedded in the concrete. It is formed by inserting a plurality of PC steel materials 6 along one main member axial direction to introduce a predetermined large prestress (see FIG. 1).

The number and position of the PC steel members 6 are determined so as to substantially coincide with the centroids of the upper and lower floor plates 3 and 4, respectively, in order to minimize the static stabilizing force generated by the main completed creep. They are inserted at predetermined intervals in the width direction of the beam 1 (see FIG. 1).

Further, the PC steel material 6 is inserted into the concrete of the upper and lower floor plates 3 and 4 in tension, respectively, and therefore, a predetermined large prestress is introduced into each of the upper and lower floor plates 3 and 4. Further, the PC steel members 6 of the adjacent upper and lower floor plates 3 and 4 are joined to each other in a tensioned state via the coupler 7, so that the joint between the upper and lower floor plates 3 and 4 has the prestress introduced into the upper and lower floor plates 3 and 4 itself. A prestress equivalent to the amount has been introduced (see FIG. 4).

Therefore, the upper and lower floor plates of the main unit 2
The upper and lower floor panels 1a and 1b consisting of the upper and lower floor panels 3, 4 are not simply introduced to each of
A predetermined amount of prestress is uniformly introduced over the entire length.

The web 5 has vertical members 8 erected on both sides in the main width direction of the upper and lower floor plates 3 and 4, and a square shape attached to both sides of the vertical members 8 in the main member axial direction. The member 9a and the inverted side member 9b and the vertical members 8,8
And an X-shaped brace material 10 attached diagonally (X-shaped) in the main width direction.

The vertical member 8, the U-shaped side member 9a, the inverted U-shaped side member 9b, and the X-shaped brace material 10 are all made of reinforced concrete using high-strength concrete in the same manner as the upper and lower floor plates 3, 4, and have a rectangular cross section. And a plurality of PC steel materials 11 are respectively inserted under tension into the concrete of the respective members, so that a predetermined large prestress is introduced into these members.

Both ends of each of the vertical member 8, the U-shaped member 9a, the inverted U-shaped member 9b, and the X-shaped brace member 10 are integrally formed on the edges of the upper and lower floor plates 3, 4, respectively. Are joined. Further, the adjacent main unit 2 has an inverted V-shaped member 9a and an inverted V-shaped member 9b are joined by a plurality of joining bolts or joining pins 12 (FIG. 5).
reference). Therefore, a web part composed of a plurality of webs 5
1c is formed in the shape of a truss that is continuous in the direction of the main one of the members, and the main cross section is also formed in the shape of a truss.

The vertical member 8, the U-shaped side member 9a, the inverted U-shaped side member 9b and the X-shaped brace member 10 are not necessarily required to have a reinforced concrete structure, but may have a steel structure made of a steel material. . Since the upper and lower floor plates 1a and 1b and the web 1c of the main girder 1 are formed in this way, the main girder 1 has a truss structure over its entire length, and also has a truss structure in the width direction of the main girder 1. ing.

FIGS. 6 and 7 show another embodiment of the main unit 2, which is mainly applied to a case in which the span of the main unit 1 is relatively small, so that the web portion 1c does not need to have much bending rigidity. Is what is done.

The details will be described below.
The upper and lower portions of the web 5 are vertically divided into two or more V-shaped web members 13a and inverted V-shaped web members 13b on the left and right sides of the upper and lower floor plates 3, 4, respectively. Each of the V-shaped web members 13a and the inverted V-shaped web member 13a and the inverted V-shaped web member 13b are mounted.
The web 5 is formed by joining each of the b and b with a plurality of joining bolts or joining pins 12 and attaching an X-shaped brace material (not shown) between the upper and lower floor plates 3 and 4 along the width direction thereof. . In addition, the configuration of the upper and lower floor plates 3 and 4 is substantially the same as the configuration of the main unit in the previous embodiment.

The V-shaped web material 13a and the inverted V-shaped web material 13b are basically made of a steel material such as an H-beam, but they are reinforced concrete or steel concrete using high-strength concrete, or prestressed steel.
In some cases (see FIG. 7).

Next, the construction method will be described step by step.

First, on the ground, the main unit 2 is assembled, and a plurality of the main units 2 are joined to a length that can be transported by a crane or the like (see FIG. 3, hereinafter referred to as “construction unit”). .

In order to join a plurality of main units 2 into a construction unit, the ends of the upper floor plate 3 of the adjacent main units 2, the ends of the lower floor plate 4 and the U-shaped side member 9 a are connected to each other. The ends of the inverted letter-shaped side member 9b are butted against each other.

Then, the PC steel members 6 of the upper floor plate 3 and the lower floor plate 4 are joined to each other by the coupler 7. At this time, instead of simply joining the PC steel members 6 together, the couplers 7 are tightened and the PC steel members 6 are attracted to each other, so that the prestresses introduced into the upper and lower floor plates 3, 4 at the joint of the upper and lower floor plates 3, 4 respectively. Introduce a prestress equivalent to the amount. The U-shaped member 9a and the inverted U-shaped member 9b are joined by a plurality of joining bolts or joining pins 12 (see FIG. 5).

Next, an assembly of the main units 2 assembled to a predetermined length, that is, a construction unit is connected to the pier 14.
With the most suitable conventional erection method in between, the construction units are bridged while joining them as needed. The joining of the construction units in such a case is performed in exactly the same manner as the joining method of the main units 2. That is, upper and lower floor boards
Prestress is introduced into the joint between the upper and lower floor plates 3, 4 by joining the PC steel members 6, 4 in a tensioned state by the coupler 7, and further, the U-shaped side member 9a is inverted from the C-shaped side member 9a.
9b is joined with a plurality of joining bolts or joining pins 12 (see FIGS. 4 and 5). FIG. 18 shows a crane erection method for bridging the main 1 using a so-called vent type shoring.

As described above, the main upper and lower floor plates 1a, 1b
Instead of introducing prestressing all at once over the entire length, prestressing is individually applied to the upper and lower floor plates 3, 4 of the main unit 2, and then to the upper and lower floor plates 3, 4 of the adjacent main unit 2, 2. Since the prestress is introduced into the joint, the prestress can be uniformly introduced over the entire length of the upper and lower floor plates 1a and 1b. Further, the prestress is not restricted by the web 5 having high rigidity, and approximately 100% of the introduced prestress can be effectively utilized.

Next, another embodiment of the PC composite truss beam according to the present invention will be described. 8 to 11, reference numeral 15
Indicates a main girder such as a bridge girder constructed in the form of a PC composite truss structure. Introduce prestressing across the floor plate
It is constructed by installing a plurality of X-shaped brace members 18 on both sides in the main width direction between 16 and 17.

The upper and lower floor boards 16 and 17 have substantially the same configuration as the upper and lower floor boards 3 and 4, but the upper and lower floor boards 3,
The concave 19 and the convex fit into each other at the approximate center of the joint 4
Each of the recesses 21 is formed at a substantially central portion of both edges in the main width direction, and is joined to an end of the X-shaped brace material 18.
Are formed respectively. The bottom of the recess 21 is formed thicker to increase the rigidity of this portion (see FIG. 11).
. The X-shaped brace material 18 has substantially the same configuration as that of the X-shaped brace material 10, and the upper and lower ends thereof are concave portions of the upper and lower floor plates 16 and 17.
It is joined to 21 by a joining bolt 22.

Next, the construction method will be described step by step.

First, PC steel members (not shown) of adjacent floor plates are joined one by one in a material axis direction of 14 mainly comprising the upper and lower floor plates 16 and 17 while being joined by a coupler (not shown). In this case, joining of the floor boards 16 and the floor boards
A prestress equivalent to the amount of prestress introduced into the floor plate 16 and the floor plate 17 is introduced by attracting and joining the PC steel materials to the joint between the 17.

By joining the floor plates 16 and 17 in this manner, a large amount of pre-stress can be introduced into the entire length of the upper and lower floor plates because the web members are not constrained at all. No stress is generated.

Next, the X-shaped brace members 18 are installed one by one between the left and right side portions between the upper and lower floor plates 16 and 17 , and the upper and lower ends thereof are fixed to the side portions of the upper and lower floor plates 16 and 17. . In this case, the upper and lower ends of the X-shaped brace material 18 are fitted into the concave portions 21 of the upper and lower floor plates 16 and 17, and are joined by joining bolts 22 (see FIGS. 11, 13, and 14).

The X-shaped brace material 18 is an X-shaped brace material.
It is formed in advance in a factory or the like in the same way as 10 but is not constrained at all in the case of a PC structure, so it is possible to introduce a necessary prestress, and harmful secondary stress due to the prestress may be generated. Absent.

Hereinafter, the same operation was performed mainly.
By repeating the process repeatedly over the entire length, the main length of 15 is constructed (see FIGS. 15, 16, and 17).

Other construction methods will be described in order.

First, the upper and lower floor plates 16 and 17 are joined one by one in the axial direction of the main member 14, and a prestress is introduced for each of the plurality of sheets (see FIG. 12). In this case, since the upper and lower floor plates 16 and 17 are not restrained at all by the web material,
Necessary prestress can be introduced, and harmful secondary stress due to prestress does not occur.

Next, a plurality of X-shaped brace members 18 are installed one by one on both left and right sides between the upper and lower floor plates 16 and 17, and the upper and lower ends are fitted into the recesses 21 of the upper and lower floor plates 16 and 17. Are joined by joining bolts 22 (see FIGS. 11, 13, and 14).
.

The X-shaped brace material 18 is an X-shaped brace material.
It is formed in advance in a factory or the like as in the case of 10, but it is possible to introduce a large amount of prestress necessary for a PC structure, and no harmful secondary stress due to the prestress is generated.

In the following, the same operation was performed.
By repeating the process repeatedly over the entire length, the main length of 15 is constructed (see FIGS. 15, 16, and 17).

[0045]

The PC according to claim 1 according to the present invention.
The composite truss structure has the above-described configuration. In particular, the upper and lower floor plates are formed by continuously connecting a plurality of floor plates formed by introducing prestress by inserting a plurality of PC steel materials, and the PCs of the adjacent floor plates are connected. Since the steel materials are joined in a tensioned state with a coupler, a prestress equivalent to the amount of prestress introduced into the floor plate is introduced into the joint between the floor plates, and each is formed, so that a predetermined amount is applied over the entire length of the main part Prestress can be evenly introduced.

Further, when prestress is introduced into the upper and lower floor panels, there is no possibility that the prestress is hardly introduced into the upper and lower floor panels by being restrained by the highly rigid web portion. In addition, a required amount of prestress can be uniformly introduced.

In addition, the web portion has vertical members on both sides between the upper and lower floor plates, and the U-shaped side members opposite to the V-shaped side members on both sides in the longitudinal direction of the floor plate portion of the vertical material. The X-shaped brace members are respectively joined to the upper and lower floor plates along the width direction of the floor plate and attached, and the adjacent V-shaped side members and the inverted V-shaped side members are respectively connected to the longitudinal direction of the upper and lower floor plate portions. And it is formed so as to form a truss structure that is continuous in the width direction. In particular, members such as the upper and lower floor boards are assembled as a main unit in advance on the ground (see Fig. 1), and multiple main units are joined and installed. As a unit (see FIG. 3), the construction unit can be extremely efficiently constructed by suspending the construction unit with a crane or the like and bridging it between piers.

Further, the PC composite truss beam according to the second aspect has the effect of reliably and evenly introducing a required amount of prestress into the upper and lower floor plates, similarly to the invention of the first aspect, and in particular, The web portion is located between the upper and lower floor plate portions.
By attaching a plurality of X-shaped bracing materials to the side portions by joining the upper and lower ends thereof to the edge portions of the adjacent upper and lower floor plates, respectively, so as to form a truss structure continuous in the material axis direction of the upper and lower floor plates. Because it is formed, it can be built very efficiently.

Further, the PC composite according to claim 1 or 2
In all truss beams, the web part forms a truss structure.
Other than the normal prestressed beam,
Presses introduced into the upper and lower floor panels after the steel structure is formed
All of the tresses are the same as for normal prestressed beams
Tension generated by the vehicle load, etc. generated in the upper and lower floor panels
It is offset by power and used effectively without waste. Also this
By doing so, the upper and lower floor plates can be made thinner and lighter.

In the construction method of the PC composite truss beam according to the third and fourth aspects of the present invention, when the upper and lower floor plates are formed, particularly, a plurality of PC steel materials are inserted to introduce a prestress to form the floor. Prestresses equivalent to the amount of prestress introduced to the floorboards are introduced into the joints between the floorboards by connecting a plurality of the floorboards in series and connecting the PC steels of the adjacent floorboards in a tensioned state with a coupler. Therefore, when introducing the prestress over the entire length of the main part, there is no possibility that the prestress is hardly introduced into the upper and lower floors by being restrained by the highly rigid web portion, and thus the upper and lower floors are surely and evenly applied to the upper and lower floors. This has the effect that a required amount of prestress can be introduced.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a main unit.

FIG. 2 is a side view of a main part.

FIG. 3 is a side view of a construction unit (an aggregate of main units) composed of a plurality of main units.

FIG. 4 is a sectional view of a joint portion of a PC steel material of a floor plate.

FIG. 5 is a cross-sectional view of a web joining portion.

FIG. 6 is an exploded side view showing another embodiment of the main unit.

FIG. 7 is a cross-sectional view of a joint of a V-shaped web material.

FIG. 8 is a side view of the main part.

FIG. 9 is a plan view of the main part.

FIG. 10 is a longitudinal sectional view of a main part.

FIG. 11 is an exploded perspective view showing a structure of a joint between a floor plate and an X-shaped brace material.

FIG. 12 is a side view showing an example of a main erection method.

FIG. 13 is a side view showing an example of a main erection method.

FIG. 14 is a side view showing an example of a main erection method.

FIG. 15 is a side view showing an example of a main erection method.

FIG. 16 is a side view showing an example of a main erection method.

FIG. 17 is a side view showing an example of a main erection method.

FIG. 18 is a side view showing an example of a main erection method.

FIG. 19 is a sectional view of a conventional main part.

FIG. 20 is a sectional view of a conventional main part.

FIG. 21 is a sectional view of a conventional main part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Main unit, 3 ... Upper floor plate, 4 ... Lower floor plate, 5 ... Web, 6 ... PC steel, 7 ... Coupler, 8 ...
Vertical member, 9a ... shaped member, 9b ... inverted shape member
9b, 10: X-shaped brace material, 11: PC steel material, 12: Joint bolt or pin, 13a: V-shaped web material, 13b: Inverted V-shaped web material, 14: Bridge pier, 15: Main girder, 16: Upper floor plate , 17 ...
Lower floor plate, 18 ... X-shaped brace material, 19 ... concave part, 20 ... convex part, 21
... recess, 22 ... joining bolt.

Claims (4)

(57) [Claims] 1. A PC composite truss beam comprising upper and lower floor plate portions formed by introducing prestress over the entire length thereof and a truss-shaped web portion between the upper and lower floor plate portions, wherein the upper and lower floor plate portions are: A plurality of floor panels formed by introducing prestress by inserting a plurality of PC steel members are connected in series, and the PC steel members of adjacent floor plates are connected to each other in a tensioned state by a coupler, thereby joining the floor plates to each other. The web portion is formed by introducing a pre-stress equivalent to the pre-stress amount introduced into the floor plate, and the web portion has a vertical member on both sides between the upper and lower floor plates, and a longitudinal direction of the floor plate portion of the vertical member. An inverted letter-shaped side member and an inverted letter-shaped side member on both sides of the plurality of X-shaped brace members are respectively attached to the upper and lower floor boards between the vertical members, and attached.
A PC composite truss beam, wherein the adjacent U-shaped side member and the inverted U-shaped side member are joined to form a truss structure. 2. A PC composite truss beam comprising upper and lower floor plates formed by introducing prestress over the entire length thereof and a truss-shaped web portion between the upper and lower floor plates, wherein the upper and lower floor plates include: A plurality of floor panels formed by introducing prestress by inserting a plurality of PC steel members are connected in series, and the PC steel members of adjacent floor plates are connected to each other in a tensioned state by a coupler, thereby joining the floor plates to each other. The web portion is formed by introducing a pre-stress equivalent to the pre-stress amount introduced into the floor plate, and the web portion has a plurality of X-shaped braces on both sides between the upper and lower floor plate portions.
A PC composite truss beam , wherein a truss structure is formed by joining and attaching materials to the floor plate . 3. A method of constructing a PC composite truss beam comprising upper and lower floor plates formed by introducing prestress over the entire length thereof and a truss-shaped web portion between the upper and lower floor plates. Upper and lower floor plates respectively formed by introducing prestress by inserting a PC steel material, and a plurality of vertical members and a U-shaped side member and an inverted V-shaped side member and an X-shaped brace material installed between the upper and lower floor plates A main unit is constructed from the above, and a plurality of the main units are connected in series, and the PC steel materials of the upper and lower floor plates of the adjacent main unit are joined to each other in a tension state with a coupler, and the floor plate is joined to the floor plate at the joint between the floor plates. A truss-like web portion is formed by introducing a prestress equivalent to the amount of prestress introduced and joining adjacent U-shaped members and inverted U-shaped members. Construction method of PC composite truss beam characterized by the following. 4. A method of constructing a PC composite truss beam comprising upper and lower floor plates formed by introducing prestress over the entire length thereof and a truss-shaped web portion between the upper and lower floor plates. A plurality of floor plates formed by introducing pre-stress by inserting PC steel materials are connected in series, and the PC steel materials of adjacent floor plates are connected to each other in a tensioned state with a coupler, so that a joint portion between floor plates is provided. Introduce a prestress equivalent to the amount of prestress introduced into the floorboard, and then between the upper and lower floorboard portions
A plurality of X-shaped brace members are joined to the upper and lower floor plates on both sides.
A truss-like web portion is formed by attaching a truss-like web portion to a PC composite truss beam.